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AME prepress abstract   -  DOI: https://doi.org/10.3354/ame01932

Increase in phytoplankton production and consumption in response to typhoon passing through the southern East China Sea

An-Yi Tsai*, Gwo-Ching Gong, Kuo-Ping Chiang

*Corresponding author:

ABSTRACT: The northwest Pacific and the East China Sea (ECS) are frequently affected by typhoons during the summer period. To identify the changes in the production and consumption rates of the phytoplankton (20~200 μm and <20 μm) affected by typhoon Maria (July 9-10, 2018), 2 sampling periods were compared: a pre-typhoon cruise during July 4-9, 2018 and a post-typhoon cruise during July 13-17, 2018. The results showed that 20~200 μm and <20 μm phytoplankton production was 14- and 1.8-fold higher in the post-typhoon period compared to the pre-typhoon period, respectively. Accompanying this post-typhoon shift from pico- and nanophytoplankton to microphytoplankton, the consumption rate of microzooplankton on <20 μm phytoplankton was 11.6 mgC m-3 d-1 in the pre-typhoon period, and it significantly increased to 203.3 mgC m-3 d-1 after the typhoon. Furthermore, the ingestion fluxes were 4.9 and 8.0 mgC m-3 d-1 through mesozooplankton grazing on microzooplankton (ciliates and dinoflagellates) pre- and post-typhoon, respectively. Our findings demonstrate that organisms from the microbial food web, such as ciliates and dinoflagellates, may control the phytoplankton assemblage during the post-typhoon increased productive period, and thus represent an important trophic intermediary between the classical and microbial food webs in the southern ECS.